Antioxidants may undermine cancer therapy

[CaroleHammett]

http://uk.reuters.com/article/healthNew ... 5620080527

Antioxidants may undermine cancer therapy

Tue May 27, 2008 10:06pm BST

NEW YORK (Reuters Health) - Cancer patients should perhaps avoid taking antioxidant supplements, a review of clinical trial data suggests, because they may diminish the effectiveness of chemotherapy and radiation treatment.

Still, findings from different studies are conflicting, so further research is warranted to determine whether antioxidants can be safely taken during cancer therapy and whether they have any benefit.

Although research looking at antioxidant use during cancer treatment has been on-going on for nearly two decades, it remains a controversial topic, note Dr. Brian D. Lawenda, from the Navel Medical Center in San Diego, California, and colleagues in their article in the Journal of the National Cancer Institute.

In researching the impact of antioxidant use on radiation therapy, the team identified three clinical studies that specifically addressed the topic.

Results from the largest of the three trials suggested that antioxidant therapy reduced overall survival. However, there was evidence indicating that one antioxidant, amifostine, can protect certain healthy tissues from radiation damage without increasing resistance in cancerous tissue.

Sixteen trials were identified that looked at the effects of antioxidant supplements on chemotherapy. There was no evidence that antioxidants reduced treatment response rates, although the authors warn that none of the studies were really large enough to address this properly.

"Despite some intriguing studies that have suggested the benefit of adjunctive antioxidant treatments in cancer patients, the totality of the available evidence is equivocal at best and leaves us with serious concerns about the potential for harm," Lawenda's team concludes.

SOURCE: Journal of the National Cancer Institute, online May 27, 2008.

© Thomson Reuters 2008.

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Submitted by Carole

[gpawelski]

There is no evidence that antioxidant supplements interfere with the therapeutic effects of chemotherapy agents, according to a systematic review of the use of antioxidants during chemotherapy, in the May, 2007 issue of the peer-reviewed journal Cancer Treatment Reviews. In fact, they may help increase survival rates, tumor response, and the patient’s ability to tolerate treatment.

This conclusion has important implications for patients whose oncologists discourage the use of antioxidant supplements during treatment. Until now, their concern has been that these supplements may counteract the tumor-shrinking abilities of the chemotherapy.

Co-author Dr. Robert Newman, Professor of Cancer Medicine at M. D. Anderson Cancer Center said,“This study, along with the evolving understanding of antioxidant-chemotherapy interactions, suggests that the previously held beliefs about interference do not pertain to clinical treatment.”

The analysis, titled “Impact of Antioxidant Supplementation on Chemotherapeutic Efficacy: A Systematic Review of the Evidence from Randomized Controlled Trials,” evaluated 845 articles from five scientific databases that examined the effects of taking natural antioxidant supplements concurrent with chemotherapy. Some of the antioxidants used in the trials included glutathione, vitamin A, vitamin C, vitamin E, ellagic acid, selenium and beta carotene.

Among the findings:

All of the studies that included survival data showed similar or better survival rates for the antioxidant group than the control group.

None of the trials supported the theory that antioxidant supplements diminish the effectiveness of chemotherapy treatments.

All but one of the studies that reported treatment response showed similar or better response in the antioxidant group than in the control group.

15 of 17 trials that assessed chemotherapy toxicities, including diarrhea, weight loss, nerve damage and low blood counts, concluded that the antioxidant group suffered similar or lower rates of these side effects than the control group.

The study noted that reducing side effects may help patients avoid having to cut back on their chemotherapy dosing, interrupt scheduled treatments, or abandon treatment altogether. This in turn, is likely to favorably impact treatment outcomes. This study encourages further exploration of the potential importance of antioxidant supplements as a means of improving cancer survival.

[CaroleHammett]

Thanks for posting this, Greg... I think.

Don't know which to believe... finally got my oncologist to "negotiate" with me on the subject now that I'm on chemo again (Alimta). I agreed to cease anti-oxident supplements (but not foods) for 5 days before and 5 days after (rather than ceasing use of them throughout the treatment period).

I have no idea which study to believe... and suspect nobody does, so will just stick with my instinct for now (which is to compromise )

Carole

[gpawelski]

Compromise is Good! The information from Johns Hopkins last year, saying Epigenetics is proving orthodox oncology wrong about supplements, adds some more fuel to the fire (about orthodox oncology). Johns Hopkins research is pretty cutting-edge.

Research on epigenetics at Johns Hopkins is proving orthodox oncology wrong about supplements. Evidence from their research suggests that the epigenome can be influenced by the environment which means that epigenetic modifications that lead to carcinogenesis may be reversible by changing the environment.

What is meant by environment? The environment is the totality of surrounding conditions - the milieu of the cell. What affects the milieu of the cell? Toxins, viruses, carcinogens, diet, essentially everything that our cells are exposed to. Detoxification followed by the creation of a healthy milieu with appropriate diet and supplements benefits cancer patients.

Such a concept is heresy to the orthodoxy within the oncology community that determines research priorities. The viability of detoxification (removing toxins, viruses, carcinogens and other biological contaminants from the body) followed by improving what a patient consumes (organic, whole, vegetarian foods, vitamin supplements, etc.) as a cancer therapy has been summarily rejected by the cancer establishment for decades (most cancer patients are offered artificially colored, sugared and preserved foods during their hospital stays).

Despite the growing empiric and anecdotal data that demonstrate that these factors do play a role in distinguishing long-term cancer survivors, the orthodoxy within the oncology community has rejected such treatment approaches as worthless. Part of their reasoning has included that there are no biological mechanisms to support such a modality. However, epigenetics is providing a plausible biological mechanism.

Is detoxification and diet a viable cancer modality by itself or in combination with other approaches? There are many long-term survivors who swear it is and offer their existence as proof. What is clear is that our body and the environment are one, as epigenetics proves, the environment can effect how our genes work within our cells.

As epigenetics has become an accepted science perhaps it is time researchers took the next step and asked what role epigenetics may play in reversing cancer and what lifestyle decisions and exposures may impact such a role. Perhaps some resources focused on the mechanistic, reductionist and overwhelmingly failed gene therapies can be redirected.

And just what is Epigenetics?

Inheritance is more than just genes. A new wave of research is unravelling the secrets beyond genes to identify what other biological information parents pass to their offspring, and cells pass on when they divide. It seems that it is not just genes that are inherited from one generation to the next but other factors that particularly affect development and disease (like cancer).

Every human being is made up of billions of tiny cells. These cells are constantly dividing and muliplying to replace dead or damaged cells. Within each cell is a complete set of all the genes that make up the coded instructions for the whole organism. Parents pass on their genetic information and associated traits to the offspring, and cells pass it on as they divide.

Because of their role in determining the functions and traits of a living organism scientists are researching genes in cell organisms to try and find out what they do. This has led to important discoveries including genes linked to breast cancer in humans.

Genes are sections of DNA. DNA looks a bit like a twisted ladder commonly called a double helix. The double helix DNA is packed into a structure called chromatin which forms chromosomes.

Research into what happens in cells has shown something remarkable. It is not just the genes that influence the traits and functions of an organism but also epigenetic or non-gene factors. These epigenetic factors are features within the cell that can be inherited when cells divide but they don't change the genes themselves. However, epigenetic factors can modify the behavior of genes. Epigenetic factors have important roles in regulating human disease.

Understanding epigenetics is fundamental to unravelling the intricacies of how genes and organisms work. Because of its fundamental nature epigenetics has broad potential implications across all the biological sciences.

Epigenetics links the fields of genetics and developmental biology. Epigenetics is the fundamental biological process by which organisms with two or more different cell types establish patterns of differential gene expression (turns on) that are stable through cell division.

Researchers discovered that chromatin, the complex formed by DNA and histones (proteins that bind strongly to DNA, thereby packaging it in chromosomes) regulate gene expression. This additional layer of regulatory instructions, which are not held in DNA, comprise the epigenetic code.

Epigenetic differences explain why two cloned organisms are not the same or why twins develop illnesses of distinct genetic origin. Epigenics not only adds to our understanding of the relations between the environment and genetics but also provides an explanation of the basic aspects of cell biology. Deciphering and understanding the epigenome will shed light on fundamental processes in cell physiology.

This knowledge will improve our understanding of the development of tumors and other diseases, and may lead to the design of new treatments for these conditions. A new family of epigenetic drugs, designed to reverse the changes in the epigenome that occur during the development of several kinds of cancer, is currently available. Several of these pharmacological agents are now being used to treat some types of leukemia and breast cancer.

Ting AH, et al, Genes Dev. 2006 Dec 1;20(23):3215-31

Szyf M., Bull Cancer. 2006 Sep 1;93(9):961-72

[Don M]

I guess I will keep on taking my antioxidants. I have been doing it for over 4 years now. And, my oncologist does not care if I do.

Don M

[CaroleHammett]

Thanks for yet more helpful information, Greg.

All in all, I consider my medical oncologist open-minded in comparison to most. The only times he has asked me to "back off" on anti-oxidents has been during active chemo (and ditto for my radiation oncologist during radiation therapy), and now he's even agreed to my continuing that (other than the 10 most critical days as noted above).

I have been extremely fortunate during the 17 months since my dx in that--despite numerous side effects--I have been relatively pain-free most of the time and have rarely (if ever) experienced cancer-fatigue (weakness, yes, but not general fatigue).

My oncologist readily admits he has absolutely no idea why I am doing so well despite inexorable progression (my health care professionals call me the "bounce back kid"). His response has been consistent: "I don't know what you're doing right, but you're doing something right and whatever it is, keep doing it!"

Carole

Life is a Terminal Condition